1. Field of the Invention
The present invention relates to an image processing apparatus and an image processing method that add an effect such as a watercolor painting to digital image data.
2. Description of the Related Art
Image processing can be performed to add a taste of a watercolor painting to digital image data. Features of the watercolor paintings may include a light color typical of the watercolor painting, a feeling of color bleeding, and further, a remaining rough line drawing. In Japanese Patent Application Laid-Open No. 2008-242533, when a predetermined closed area is colored, the colored area is moved in a random direction by a predetermined distance, the colored area is set at a location which deviates from the closed area, and the colored area is colored with a light color toward the periphery from the center of the colored area.
Thus, the Laid-Open No. 2008-242533 proposes a method that can express the color bleeding feeling of the paints. Further, in Japanese Patent Application Laid-Open No. 11-232441, images are spatially grouped according to a similar color and color subtraction is performed in the same group so that the images are represented by one same color. Thus, the Laid-Open No. 11-232441 proposes a method that expresses a taste of the watercolor painting which is realized by limited paints.
In the method of Japanese Patent Application Laid-Open No. 2008-242533, since all color information is first lost before coloring, the taste of the watercolor paintings may be expressed with the small number of colors. However, since the colored area has a color different from an input image, it is difficult to retain an atmosphere of the input image. In Japanese Patent Application Laid-Open No. 11-232441, while the number of colors is certainly decreased, boundaries between the groups, that is, edges, are expressed by generating a mixed color by colors represented by the respective groups. By this method, the boundaries are fused, and as a result, it is difficult to express the effect of the rough line drawing.